Document handling operations typically involve transporting material units such as sheet articles along one for more flow paths, and through a number of different stations or modules. Each module performs a different operation on sheet articles. Examples include printing, turning, scanning, folding, staging, accumulating, envelope stuffing, binding, and the like. Because of the functions performed by such modules and the need for transporting sheet articles to and from the modules as well as through the physical structure of the modules, various types of physical contact with the sheet articles necessarily occur that could damage and/or smudge the sheet articles and/or cause the sheet articles to deviate from their intended paths. These interactions occur between the sheet articles and the components comprising the modules, and also between the sheet articles and the conveying devices employed to transport the sheet articles. Hence, proper control over the handling of sheet articles is a primary consideration when designing document processing equipment and subsequently operating such equipment. Problems attending the control over sheet articles can become exacerbated when the sheet articles are to be processed at different speeds among the various modules and even within the same module. For example, sheet articles often must be inputted into a given module at a speed matched with the speed of the preceding module, brought to an abrupt stop within the given module for the purposes of staging and/or accumulation, and then brought back up to a speed at which the sheet articles can be transferred to a succeeding module. Accordingly, there continues to be a widely recognized need for devices and methods for improving control over the transportation and handling of sheet articles in order to minimize damage, smudging and/or excessive skewing.
The present invention is provided to address, in whole or in part, these and other problems associated with prior art document handling technology.